The present disclosure relates to an optical recording medium including a phase-change recording layer.
In recent years, a technique for multilayering a recording layer has been widely used in optical recording media in order to further increase storage capacity. Studies on the multilayering technique have been advanced for various optical recording media of a reproduction-only type, a write-once type, and a rewritable type.
A rewritable multilayered optical recording medium including a two-layer structure recording layer has been proposed, in which a first recording layer (L0 layer), an intermediate layer, a second recording layer (L1 layer), and a light-transmissive layer are stacked in that order on a substrate. The optical recording medium with a two-layer structure uses as the second recording layer a recording layer (properly referred to as a “semi-transmissive recording layer” hereinafter) which can transmit a laser beam used for recording/reproduction on/from the first recording layer.
The second recording layer includes a stack of a dielectric material, a metal, and a phase-change recording material, etc. so that recording/reproduction performance can be exhibited. Typically, the second recording layer has a structure in which a first dielectric layer, a metal reflective layer, a second dielectric layer, a phase-change recording layer, and a third dielectric layer are stacked in that order on a substrate (for example, refer to International Publication No. 2008/018225).